The present invention relates to an ironing apparatus and more particularly, to such an ironing apparatus which may form a cup-like article such as an one-piece metallic can body without causing uneven thickness in the circumferential direction of the sidewall portion thereof.
In an ironing apparatus for forming a redrawn-ironed metallic can body to be used for beer cans, carbonated drinks cans and the like, a ram having a punch on the tip thereof is usually adapted to reciprocate in the horizontal direction. The ram is usually elongated, e.g. 50 mm in diameter and 1.35 m long, and thus curves downwardly with gravity during its reciprocal movement (refer to FIG. 5).
Conventionally a ring die 2 cooperating with the punch for forming an ironed metallic can body is disposed vertically, e.g. such that the axis 2x thereof extends in the horizontal direction, as shown in FIG. 1. Consequently, even if the die 2 is radially aligned with the punch 1 such that the axes thereof virtually coincide with each other at the location of the die 2, and an entry portion 3a of the sidewall portion 3 of the can body under forming has a uniform thickness in the circumferential direction, an exit portion 3b of the sidewall portion 3 which is formed with the punch 1 moving in the arrow direction A, e.g. slightly downwardly, tends to have uneven circumferential thickness such that an upper portion 3b.sub.1 thereof be somewhat thicker than a lower portion 3b.sub.2.
Since the sidewall portion of an ironed metallic can body is usually very thin, e.g. 0.10 to 0.15 mm thick, the aforementioned uneven circumferential thickness is apt to damage the appearance of the can body due to ruggedness of the sidewall portion caused by the difference of reduction in the circumferential direction, and incur troubles such as the decrease of strength or rupture at an especially thin portion such as the lower portion 3b.sub.2 of the formed sidewall portion.